This invention relates to an air conditioning or refrigeration system, and more particularly to the method and means for precooling or subcooling refrigerant in a refrigeration or air conditioning system.
Heretofore, subcoolers have been provided in air conditioning systems for subcooling refrigerant. Such subcoolers have usually been provided between the condenser and the evaporator for reducing the temperature of the liquid refrigerant supplied to the evaporator to a temperature lower than the temperature of the liquid refrigerant discharged from the condenser thereby to decrease the air conditioning cycle time and the amperage required for operation of the air conditioning system.
For example, U.S. Pat. No. 4,316,366, to John D. Manning, dated Feb. 23, 1982, and U.S. Pat. No. 4,357,805, to John D. Manning, dated Nov. 9, 1982 are both directed to a flash subcooler in which a portion of liquid refrigerant circulating from the condenser to the evaporator is diverted to the subcooler where it is flashed while the main body of liquid refrigerant flows in a straight line direction through the subcooler in a minimum of time. As the refrigerant changes state from a liquid to a gas, it absorbs heat energy from the refrigerant flowing from the condenser to the evaporator subcooling the main body of liquid refrigerant. The diverted portion of the liquid refrigerant is vaporized or flashed and results in the subcooling of the main body of liquid refrigerant which subsequently enters the evaporator. By subcooling the liquid refrigerant to the evaporator the capacity of a given flow rate to absorb heat energy in the evaporator is increased. The flashed or vaporized refrigerant from both the subcooler and the evaporator are drawn or returned to the compressor through a common suction line.
U.S. Pat. No. 4,577,468, dated Mar. 25, 1986 is likewise directed to a subcooler for subcooling liquid refrigerant from a condenser to an evaporator and diverts a small portion of the main body of liquid refrigerant through the subcooler where it is vaporized for cooling the main body of liquid refrigerant. The subcooler includes small U-shaped concentric inner and outer cylinderical tubes with the vaporized refrigerant in the inner tube flowing directly along the longitudinal axis of the inner tube in parallel relation thereto for cooling the main body of liquid refrigerant flowing in the annulus between the inner and outer tubes along the longitudinal axis of the tubes. FIG. 2 of U.S. Pat. No. 4,577,468 discloses an arrangement in which the vaporized refrigerant leaving the subcooler flows to a separate receiver for further cooling of the liquid refrigerant before the liquid refrigerant enters the evaporator.
Other similar patents included Lathrop U.S. Pat. No. 2,388,556, dated Nov. 6, 1945 which shows a refrigerating system including a subcooler for cooling the refrigerant gas between a low pressure compressor and an a high pressure compressor for a multi-stage compression refrigerating system. The subcooler cools the compressed refrigerant discharged from the low pressure compressor before it enters the intake of the high pressure compressor to remove excess heat from the low pressure gas. The liquid refrigerant is partially flashed in the subcooler and the flashed vaporized refrigerant is drawn off at the high stage compressor suction pressure to the high stage compressor.
U.S. Pat. No. 2,051,971, dated Aug. 25, 1936 relates to a refrigeration system having a heat interchanger which precools liquid refrigerant before the liquid refrigerant is delivered to the expansion valve for the evaporator with the liquid refrigerant being cooled by vaporized refrigerant from the suction line of the evaporator.